Vector and Matrix Utils #85

vector_add vector_sub vector_mul vector_div

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:dot_prod line 14: this:vector_mul

Source

":vector_add(V1 [,V2 ...]) => VN such that VN[n] = V1[n] + V2[n]...";
":vector_sub(V1 [,V2 ...]) => VN such that VN[n] = V1[n] - V2[n]...";
":vector_mul(V1 [,V2 ...]) => VN such that VN[n] = V1[n] * V2[n]...";
":vector_div(V1 [,V2 ...]) => VN such that VN[n] = V1[n] / V2[n]...";
"Vectors do not need to be the same length, but they should be. VN's length will be the length of the longest vector in the arguments. :vector_add and :vector_sub will pad out the smaller vectors with 0's or 0.0's. :vector_mul and :vector_div will pad out the smaller vectors with 1's or 1.0's. Vectors do not need to contain homogeneous data, but the nth term of each vector must be of the same type.";
"I can see a reason for wanting to do vector addition or subtraction, but multiplication and divareion is usually handled in other ways. I've included them here for novelty, and becuase it was easy enough to do.";
"";
"Vector addition is used when two or more similar vector quantities are at work and need to be resolved into a single vector. For instance, a ship travelling in a current will be acted upon by (at least) two forces: a force propelling it forward (its engine), and a force pushing it off course (the current). The sum of these two forces gives the resultant net force acting upon the ship and, since Force = Mass * Acceleration, the direction the ship is accelerating.";
"";
"Vector subtraction can be used to reverse the process of vector addition. In the ship problem above, let's say the actual resultant force is known, but it does not match the result of adding the propelling force and the drifting force. Friction is probably acting against the motion of the ship. Subtracting the computed resultant force from the known net force will yield the frictional force acting against the progress of the ship.";
"";
"Vector multiplication and division do not have RL examples, but vector multiplication of this type makes computing the dot product of two vectors simple.";
"";
if (length(args) == 1)
return args;
elseif (!args)
return raise(E_INVARG);
endif
type = verb[$ - 2..$];
lresult = max = length(args[1]);
results = args[1];
for n in [2..length(args)]
if (type == "add")
for m in [1..min(lcurr = length(args[n]), lresult)]
results[m] = results[m] + args[n][m];
endfor
if (lcurr > lresult)
results[lresult + 1..lcurr] = args[n][lresult + 1..lcurr];
endif
elseif (type == "sub")
for m in [1..min(lcurr = length(args[n]), lresult)]
results[m] = results[m] - args[n][m];
endfor
if (lcurr > lresult)
for m in [lresult + 1..lcurr]
results = {@results, -args[n][m]};
endfor
endif
elseif (type == "mul")
for m in [1..min(lcurr = length(args[n]), lresult)]
results[m] = results[m] * args[n][m];
endfor
if (lcurr > lresult)
results[lresult + 1..lcurr] = args[n][lresult + 1..lcurr];
endif
else
for m in [1..min(lcurr = length(args[n]), lresult)]
results[m] = results[m] / args[n][m];
endfor
if (lcurr > lresult)
for m in [lresult + 1..lcurr]
results = {@results, (typeof(foo = args[n][m]) == INT) ? 1 / foo | (1.0 / foo)};
endfor
endif
endif
endfor
return results;

matrix_add matrix_sub

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":matrix_add(M1 [, M2 ...]) => MN such that MN[m][n] = M1[m][n] + M2[m][n]...";
":matrix_sub(M1 [, M2 ...]) => MN such that MN[m][n] = M1[m][n] - M2[m][n]...";
"Matrices should all be of the same size.";
"";
"Matrix addition and subtraction is simply the addition or subtraction of the vectors contained in the matrices. See 'help $matrix_utils:vector:add' for more help.";
type = verb[$ - 2..$];
results = args[1];
if (typeof(results[1][1]) == LIST)
for n in [1..length(results)]
results[n] = this:(verb)(results[n], @$list_utils:slice(args[2..$], n));
endfor
else
for n in [1..length(results)]
results[n] = this:("vector_" + type)(results[n], @$list_utils:slice(args[2..$], n));
endfor
endif
return results;

transpose

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":transpose(Mmn) => Mnm";
"Transpose an m by n matrix into an n by m matrix by making the rows in the original the columns in the output.";
{mat} = args;
if (!this:is_matrix(mat))
return raise("E_INVMAT", "Invalid Matrix Format");
endif
j = this:dimensions(mat)[2];
result = {};
for n in [1..j]
result = {@result, this:column(mat, n)};
endfor
return result;

determinant

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:determinant line 34: this:determinant
• #85:inverse line 9: this:determinant
• #85:inverse line 14: this:determinant
• #85:cross_prod line 28: this:determinant

Source

":determinant(M) => NUM the determinant of the matrix.";
"";
"There are several properties of a matrix's determinant. Adding or subtracting a row or column from another row or colum of a matrix does not hange the value of its determinant. Multiplying a row or column of a matrix by a single scalar value has the effect of multiplying the matrix's determinant by the same scalar.";
"";
"However, the most dramatic use of determinants is in solving linear equations. For example, the solution to this system of equations:";
"";
"Ax1 + Bx2 + Cx3 = D";
"Ex1 + Fx2 + Gx3 = H";
"Ix1 + Jx2 + Kx3 = L";
"";
"is";
"";
"     1 |D B C|         1 |A D C|        1 |A B D|";
"x1 = - |H F G|    x2 = - |E H G|   x3 = - |E F H|";
"     Z |L J K|         Z |I L K|        Z |I J L|";
"";
"          |A B C|";
"where Z = |E F G|";
"          |I J K|";
"";
"or, in other words, x1, x2, and x3 are some determinant divided by Z, another determinant.";
"";
"Determinants are also used in computing the cross product of two vectors. See 'help $matrix_utils:cross_prod' for more info.";
"";
{mat} = args;
if (!this:is_square(mat))
return raise("E_INVMAT", "Invalid Matrix Format");
elseif (this:dimensions(mat)[1] == 2)
return (mat[1][1] * mat[2][2]) - (mat[1][2] * mat[2][1]);
else
result = 0;
coeff = 1;
for n in [1..length(mat[1])]
result = result + ((coeff * mat[1][n]) * this:determinant(this:submatrix(1, n, mat)));
coeff = -coeff;
endfor
return result;
endif

inverse

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":inverse(M) => MN such that M * MN = I";
"";
"The inverse of a matrix is very similar to the reciprocal of a scalar number. If two numbers, A and B, equal 1 (the scalar identity number) when multiplied together (AB=1), then B is said the be the reciprocal of A, and A is the reciprocal of B. If A and B are matrices, and the result of multiplying them togeter is the Identity Matrix, then B is the inverse of A, and A is the inverse of B.";
"";
"Computing the inverse involves the solutions of several linear equations. Since linear equations can be easily solved with determinants, this is rather simple. See 'help $matrix_utils:determinant' for more on how determinants solve linear equations.";
"";
{mat} = args;
{i, j} = this:dimensions(mat);
det = this:determinant(mat);
result = {};
for k in [1..i]
sub = {};
for l in [1..j]
sub = {@sub, (tofloat($math_utils:pow(-1, i + j)) * this:determinant(this:submatrix(j, i, mat))) / det};
endfor
result = {@result, sub};
endfor
return result;

identity

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":identity(INT <size>) => Identity matrix (I) of dimensions <size> by <size>.";
"All elements of I are 0, except for the diagonal elements which are 1.";
"";
"The Identity Matrix has the unique property such that when another matrix is multiplied by it, the other matrix remains unchanged. This is similar to the number 1. a*1 = a. A * I = A, if the dimensions of I and A are the same.";
"";
n = args[1];
result = this:null(n, n);
for i in [1..n]
result[i][i] = 1;
endfor
return result;

null

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:identity line 7: this:null

Source

":null(INT <size>) => Null matrix (O) of dimensions <size> by <size>.";
"All elements of O are 0.";
"";
"The Null Matrix has the property that is equivalent to the number 0; it reduces the original matrix to itself. a * 0 = 0. A * N = N.";
"";
{m, ?n = m} = args;
result = {};
for i in [1..m]
result = {@result, {}};
for j in [1..n]
result[i] = {@result[i], 0};
endfor
endfor
return result;

is_square

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:determinant line 26: this:is_square
• #85:is_null line 3: this:is_square
• #85:is_identity line 3: this:is_square
• #85:is_reflexive line 5: this:is_square
• #85:is_symmetric line 5: this:is_square
• #85:is_transitive line 5: this:is_square

Source

":is_square(M) => 1 iff dimensions of M are equal to each other.";
{m} = args;
return (this:is_matrix(m) && (this:order(m) == 2)) && ((dim = this:dimensions(m))[1] == dim[2]);

is_null

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":is_null(M) => 1 iff M is O.";
m = length(mat = args[1]);
if (!this:is_square(mat))
return 0;
endif
for i in [1..m]
for j in [1..m]
if (mat[i][j] != 0)
return 0;
endif
endfor
endfor
return 1;

is_identity

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":is_identity(M) => 1 iff M is I.";
m = length(mat = args[1]);
if (!this:is_square(mat))
return 0;
endif
for i in [1..m]
for j in [1..m]
if ((mat[i][j] != 0) && ((i != j) ? 1 | (mat[i][j] != 1)))
return 0;
endif
endfor
endfor
return 1;

cross_prod outer_prod vector_prod

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":cross_prod(V1, V2) => VN, the vector perpendicular to both V1 and V2 with length equal to the area of the parallelogram spanned by V1 and V2, and direction governed by the rule of thumb.";
"";
"If A = a1i + a2j + a3k, represented as a list as {a1, a2, a3}";
"and B = b1i + b2j + b3k, or {b1, b2, b3}, then";
"";
"        |i  j  k |";
"A x B = |a1 a2 a3| = |a2 a3|i - |a1 a3|j + |a1 a2|k";
"        |b1 b2 b3| = |b2 b3|    |b1 b3|    |b1 b2|";
"";
"or, in list terms, as the list of the coefficients of i, j, and k.";
"";
"Note: i, j, and k are unit vectors in the x, y, and z direction respectively.";
"";
"The rule of thumb: A x B = C  If you hold your right hand out so that your fingers point in the direction of A, and so that you can curl them through B as you make a hitchhiking fist, your thumb will point in the direction of C.";
"";
"Put another way, A x B = ABsin(THETA) (A cross B equals the magnitude of A times the magnitude of B times the sin of the angle between them) This is expressed as a vector perpendicular the the A-B plane, pointing `up' if you curl your right hand fingers from A to B, and `down' if your right hand fingers curl from B to A.";
"";
"The cross product has many uses in physics. Angular momentum is the cross product of a particles position vector from the point it is rotating around and it's linear momentum (L = r x p). Torque is the cross product of position and Force (t = r x F).";
"";
{v1, v2} = args;
if (((((l = length(v1)) != length(v2)) || (l != 3)) || (!this:is_vector(v1))) || (!this:is_vector(v2)))
return raise("E_INVVEC", "Invalid Vector Format");
endif
mat = {{1, 1, 1}, v1, v2};
coeff = 1;
result = {};
for n in [1..3]
result = {@result, coeff * this:determinant(this:submatrix(1, n, mat))};
coeff = -coeff;
endfor
return result;

norm length

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:subtended_angle line 11: this:norm
• #85:subtended_angle line 11: this:norm

Source

":norm(V) => FLOAT";
":length(V) => FLOAT";
"The norm is the length of a vector, the square root of the sum of the squares of its elements.";
"";
"In school, we all should have learned the Pythagorean Theorem of right triangles: The sum of the squares of the sides of a right triagle is equal to the square of the hypoteneuse. The Theorem holds true no matter how many dimensions are being considered. The length of a vector is equal to the square root of the sum of the squares of its components. The dot product of a vector with itself happens to be the sum of the squares of its components.";
"";
{v} = args;
return this:is_vector(v) ? sqrt(tofloat(this:dot_prod(v, v))) | E_TYPE;

submatrix

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:determinant line 34: this:submatrix
• #85:inverse line 14: this:submatrix
• #85:cross_prod line 28: this:submatrix

Source

":submatrix(i, j, M1) => M2, the matrix formed from deleting the ith row and jth column from M1.";
{i, j, mat} = args;
{k, l} = this:dimensions(mat);
result = {};
for m in [1..k]
sub = {};
for n in [1..l]
if ((m != i) && (n != j))
sub = {@sub, mat[m][n]};
endif
endfor
if (sub)
result = {@result, sub};
endif
endfor
return result;

dot_prod inner_prod scalar_prod

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:norm line 8: this:dot_prod
• #85:subtended_angle line 11: this:dot_prod
• #85:matrix_mul line 15: this:dot_prod

Source

":dot_prod(V1, V2) => NUM";
":inner_prod(V1, V2) => NUM";
"The dot, or inner, product of two vectors is the sum of the products of the corresponding elements of the vectors.";
"If V1 = {1, 2, 3} and V2 = {4, 5, 6}, then V1.V2 = 1*4 + 2*5 + 3*6 = 32";
"";
"The dot product is useful in computing the angle between two vectors, and the length of a vector. See 'help $matrix_utils:subtended_angle' and 'help $matrix_utils:length'.";
"";
"A . B = ABcos(THETA)  (A dot B equals the magnitude of A times the magnitude of B times the cosine of the angle between them.)";
"";
{v1, v2} = args;
if ((((l = length(v1)) != length(v2)) || (!this:is_vector(v1))) || (!this:is_vector(v2)))
return raise("E_INVVEC", "Invalid Vector Format");
endif
temp = this:vector_mul(v1, v2);
result = (typeof(temp[1]) == INT) ? 0 | 0.0;
for n in [1..l]
result = result + temp[n];
endfor
return result;

dimension*s

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":dimensions(M) => LIST of dimensional sizes.";
l = {length(m = args[1])};
if (typeof(m[1]) == LIST)
l = {@l, @this:dimensions(m[1])};
endif
return l;

order

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:is_square line 3: this:order

Source

":order(M) => INT how many dimensions does this matrix have? 1 means vector";
return length(this:dimensions(args[1]));

scalar_vector_add scalar_vector_sub scalar_vector_mul scalar_vector_div

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":scalar_vector_add(S, V) => VN such that VN[n] = V[n] + S...";
":scalar_vector_sub(S, V) => VN such that VN[n] = V[n] - S...";
":scalar_vector_mul(S, V) => VN such that VN[n] = V[n] * S...";
":scalar_vector_div(S, V) => VN such that VN[n] = V[n] / S...";
"Actually, arguments can be (S, V) or (V, S). Each element of V is augmented by S. S should be either an INT or a FLOAT, as appropriate to the values in V.";
"";
"I can see a reason for wanting to do scalar/vector multiplcation or division, but addition and subtraction between vector and scalar types is not done. I've included them here for novelty, and because it was easy enough to to.";
"";
"Scalar-vector multiplication stretches a vector along its direction, generating points along a line. One of the more famous uses from physics is Force equals mass times acceleration. F = ma. Force and acceleration are both vectors. Mass is a scalar quantity.";
"";
if (typeof(args[1]) == LIST)
{vval, sval} = args;
else
{sval, vval} = args;
endif
if (!this:is_vector(vval))
return raise("E_INVVEC", "Invalid Vector Format");
endif
type = verb[$ - 2..$];
for n in [1..length(vval)]
if (type == "add")
vval[n] = vval[n] + sval;
elseif (type == "sub")
vval[n] = vval[n] - sval;
elseif (type == "mul")
vval[n] = vval[n] * sval;
else
vval[n] = vval[n] / sval;
endif
endfor
return vval;

subtended_angle

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":subtended_angle(V1, V2) => FLOAT smallest angle defined by V1, V2 in radians";
"";
"Any two vectors define two angles, one less than or equal to 180 degrees, the other 180 degrees or more. The larger can be determined from the smaller, since their sum must be 360 degrees.";
"";
"The dot product of the two angles, divided by the lengths of each of the vectors is the cosine of the smaller angle defined by the two vectors.";
"";
{v1, v2} = args;
if ((((l = length(v1)) != length(v2)) || (!this:is_vector(v1))) || (!this:is_vector(v2)))
return raise("E_INVVEC", "Invalid Vector Format");
endif
return acos(tofloat(this:dot_prod(v1, v2)) / (this:norm(v1) * this:norm(v2)));

column

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:transpose line 10: this:column
• #85:matrix_mul line 15: this:column

Source

":column(M, INT <n>) => LIST the nth column of M.";
{mat, i} = args;
j = this:dimensions(mat)[1];
result = {};
for m in [1..j]
result = {@result, mat[m][i]};
endfor
return result;

matrix_mul

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":matrix_mul(M1, M2) => MN such that MN[m][n] = the dot product of the mth row of M1 and the transpose of thenth column of M2.";
"";
"Matrix multiplication is the most common and complex operation performed on two matrices. First, matrices can only be multiplied if they are of compatible sizes. An i by j matrix can only be multiplied by a j by k matrix, and the results of this multiplication will be a matrix of size i by k. Each element in the resulting matrix is the dot product of a row from the first matrix and a column from the second matrix. (See 'help $matrix_utils:dot_prod'.)";
"";
{m1, m2} = args;
{i, j} = this:dimensions(m1);
{k, l} = this:dimensions(m2);
if (((j != k) || (!this:is_matrix(m1))) || (!this:is_matrix(m2)))
return raise("E_INVMAT", "Invalid Matrix Format");
endif
result = {};
for m in [1..i]
sub = {};
for n in [1..l]
sub = {@sub, this:dot_prod(m1[m], this:column(m2, n))};
endfor
result = {@result, sub};
endfor
return result;

scalar_matrix_mul scalar_matrix_div

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":scalar_matrix_add(S, M) => MN such that MN[m][n] = MN[m][n] + S...";
":scalar_matrix_sub(S, M) => MN such that MN[m][n] = MN[m][n] - S...";
":scalar_matrix_mul(S, M) => MN such that MN[m][n] = MN[m][n] * S...";
":scalar_matrix_div(S, M) => MN such that MN[m][n] = MN[m][n] / S...";
"Actually, arguments can be (S, M) or (M, S). Each element of M is augmented by S. S should be either an INT or a FLOAT, as appropriate to the values in M.";
"I can see a reason for wanting to do scalar/matrix multiplication or division, but addition and subtraction between matrix and scalar types is not done. I've included them here for novelty, and because it was easy enough to do.";
type = verb[$ - 2..$];
if (typeof(args[1]) == LIST)
{mval, sval} = args;
else
{sval, mval} = args;
endif
if (!this:is_matrix(mval))
return raise("E_INVMAT", "Invalid Matrix Format");
endif
results = {};
if (typeof(mval[1][1] == LIST))
for n in [1..length(mval)]
results = {@results, this:(verb)(mval[n], sval)};
endfor
else
for n in [1..length(mval)]
results = {@results, this:("scalar_vector_" + type)(mval[n], sval)};
endfor
endif
return results;

is_matrix

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:transpose line 4: this:is_matrix
• #85:is_square line 3: this:is_matrix
• #85:matrix_mul line 8: this:is_matrix
• #85:matrix_mul line 8: this:is_matrix
• #85:scalar_matrix_mul line 13: this:is_matrix

Source

"A matrix is defined as a list of vectors, each having the smae number of elements.";
{m} = args;
if ((typeof(m) != LIST) || (typeof(m[1]) != LIST))
return 0;
endif
len = length(m[1]);
for v in (m)
if ((!this:is_vector(v)) || (length(v) != len))
return 0;
endif
endfor
return 1;

is_vector

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:cross_prod line 21: this:is_vector
• #85:cross_prod line 21: this:is_vector
• #85:norm line 8: this:is_vector
• #85:dot_prod line 11: this:is_vector
• #85:dot_prod line 11: this:is_vector
• #85:scalar_vector_add line 16: this:is_vector
• #85:subtended_angle line 8: this:is_vector
• #85:subtended_angle line 8: this:is_vector
• #85:is_matrix line 8: this:is_vector

Source

"A vector shall be defined as a list of INTs or FLOATs. (I'm not gonna worry about them all being the same type.)";
flag = 1;
{v} = args;
if (typeof(v) != LIST)
return 0;
endif
for n in (v)
if (((ntype = typeof(n)) != INT) && (ntype != FLOAT))
flag = 0;
break;
endif
endfor
return flag;

is_reflexive is_areflexive

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:is_partial_ordering line 3: this:is_reflexive

Source

":is_reflexive   (M) => 1 if M is a reflexive relation, -1 if areflexive,";
"                       0 otherwise.";
":is_areflexive does the same, but with 1 and -1 reversed.";
{m} = args;
if (!this:is_square(m))
return raise("E_INVMAT", "Invalid Matrix Format");
endif
good = bad = 0;
for n in [1..length(m)]
if (!m[n][n])
bad = 1;
else
good = 1;
endif
endfor
return this:_relation_result(good, bad, verb[4] == "a");

is_symmetric is_asymmetric

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:is_partial_ordering line 3: this:is_asymmetric

Source

":is_symmetric   (M) => 1 if M is a symmetric relation, -1 if asymmetric,";
"                       0 otherwise.";
":is_asymmetric does the same, but with 1 and -1 reversed.";
{mat} = args;
if (!this:is_square(mat))
return raise("E_INVMAT", "Invalid Matrix Format");
endif
good = bad = 0;
for m in [1..len = length(mat)]
for n in [m + 1..len]
if (mat[m][n] == mat[n][m])
good = 1;
else
bad = 1;
endif
endfor
endfor
return this:_relation_result(good, bad, verb[4] == "a");

is_transitive is_atransitive

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:is_partial_ordering line 3: this:is_transitive

Source

":is_transitive  (M) => 1 if M is a transitive relation, -1 if atransitive,";
"                       0 otherwise.";
":is_atransitive does the same, but with 1 and -1 reversed.";
{mat} = args;
if (!this:is_square(mat))
return raise("E_INVMAT", "Invalid Matrix Format");
endif
good = bad = 0;
for m in [1..len = length(mat)]
for n in [1..len]
if (mat[m][n])
for l in [1..len]
if (mat[n][l])
if (mat[m][l])
good = 1;
else
bad = 1;
endif
endif
endfor
endif
endfor
endfor
return this:_relation_result(good, bad, verb[4] == "a");

_relation_result

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

• #85:is_reflexive line 16: this:_relation_result
• #85:is_symmetric line 18: this:_relation_result
• #85:is_transitive line 24: this:_relation_result

Source

"Common code for is_reflexive, is_symmetric, and is_transitive.";
{good, bad, flag} = args;
if (good && (!bad))
result = 1;
elseif ((!good) && bad)
result = -1;
else
result = 0;
endif
return flag * result;

is_partial_ordering

Spec this none thisFlags rxdOwner #29Definer #85

Referenced by

none

Source

":is_partial_ordering(M) => 1 iff M is a reflexive, asymmetric, transitive relation.";
{mat} = args;
return ((this:is_asymmetric(mat) == this:is_reflexive(mat)) == this:is_transitive(mat)) == 1;

xyzr_collision

Spec this none thisFlags rxdOwner #361Definer #85

Referenced by

none

Source

":xyzr_collision({x1,y1,z1,r1},{x2,y2,z2,r2}) => 1|0";
{a, b} = args;
{x, y, z} = {b[1] - a[1], b[2] - a[2], b[3] - a[3]};
dist2 = ((x * x) + (y * y)) + (z * z);
radsum = a[4] + b[4];
"spheres collide if squared distance is less than squared radii";
return dist2 <= (radsum * radsum);

xyz_distance

Spec this none thisFlags rxdOwner #361Definer #85

Referenced by

• #285:calc_ratio line 3: $vu:xyz_distance

Source

":xyz_distance({x1,y1,z1},{x2,y2,z2}) => float dist";
{a, b} = args;
{x, y, z} = {b[1] - a[1], b[2] - a[2], b[3] - a[3]};
return sqrt(tofloat(((x * x) + (y * y)) + (z * z)));

xyz_line

Spec this none thisFlags rxdOwner #361Definer #85

Referenced by

none

Source

":xyz_line({x1,y1,z1},{x2,y2,z2}) => { {x,y,z}, {x,y,z}, ... }";
"returns a list of xyz coordinates through which one would travel to get from args[1] to args[2]. i.e. how to get from A to B on an integer grid.";
"internally, the function uses Bresenham's Line Algorithm.";
{a, b} = args;
cursor = a;
result = {};
dist = {b[1] - a[1], b[2] - a[2], b[3] - a[3]};
x_inc = (dist[1] < 0) ? -1 | 1;
y_inc = (dist[2] < 0) ? -1 | 1;
z_inc = (dist[3] < 0) ? -1 | 1;
lmn = {abs(dist[1]), abs(dist[2]), abs(dist[3])};
dist2 = {2.0 ^ lmn[1], 2.0 ^ lmn[2], 2.0 ^ lmn[3]};
if ((lmn[1] >= lmn[2]) && (lmn[1] >= lmn[3]))
err1 = dist2[2] - tofloat(lmn[1]);
err2 = dist2[3] - tofloat(lmn[1]);
for i in [1..lmn[1]]
result = {@result, cursor};
if (err1 > 0.0)
cursor[2] = cursor[2] + y_inc;
err1 = err1 - dist2[1];
endif
if (err2 > 0.0)
cursor[3] = cursor[3] + z_inc;
err2 = err2 - dist2[1];
endif
err1 = err1 + dist2[2];
err2 = err2 + dist2[3];
cursor[1] = cursor[1] + x_inc;
endfor
elseif ((lmn[2] >= lmn[1]) && (lmn[2] >= lmn[3]))
err1 = dist2[1] - tofloat(lmn[2]);
err2 = dist2[3] - tofloat(lmn[2]);
for i in [1..lmn[2]]
result = {@result, cursor};
if (err1 > 0.0)
cursor[1] = cursor[1] + x_inc;
err1 = err1 - dist2[2];
endif
if (err2 > 0.0)
cursor[3] = cursor[3] + z_inc;
err2 = err2 - dist2[2];
endif
err1 = err1 + dist2[1];
err2 = err2 + dist3[2];
cursor[2] = cursor[2] + y_inc;
endfor
else
err1 = dist2[2] - tofloat(lmn[3]);
err2 = dist2[1] - tofloat(lmn[3]);
for i in [1..lmn[3]]
result = {@result, cursor};
if (err1 > 0.0)
cursor[2] = cursor[2] + y_inc;
err1 = err1 - dist2[3];
endif
if (err2 > 0.0)
cursor[1] = cursor[1] + x_inc;
err2 = err2 - dist2[3];
endif
err1 = err1 + dist2[2];
err2 = err2 + dist2[1];
cursor[3] = cursor[3] + z_inc;
endfor
endif
result = {@result, cursor};
return result;