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libgeometry: add matrix minor and cofactor functions

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This commit is contained in:
rodri 2023-12-20 11:27:36 +00:00
parent 34e7b54c13
commit e94d21ee3a
3 changed files with 66 additions and 1 deletions
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4
sys/include/geometry.h
View file

@ -84,6 +84,8 @@ void smulm(Matrix, double);
void transposem(Matrix);
double detm(Matrix);
double tracem(Matrix);
double minorm(Matrix, int, int);
double cofactorm(Matrix, int, int);
void adjm(Matrix);
void invm(Matrix);
Point2 xform(Point2, Matrix);
@ -97,6 +99,8 @@ void smulm3(Matrix3, double);
void transposem3(Matrix3);
double detm3(Matrix3);
double tracem3(Matrix3);
double minorm3(Matrix3, int, int);
double cofactorm3(Matrix3, int, int);
void adjm3(Matrix3);
void invm3(Matrix3);
Point3 xform3(Point3, Matrix3);

26
sys/man/2/geometry
View file

@ -1,6 +1,6 @@
.TH GEOMETRY 2
.SH NAME
Flerp, fclamp, Pt2, Vec2, addpt2, subpt2, mulpt2, divpt2, lerp2, dotvec2, vec2len, normvec2, edgeptcmp, ptinpoly, Pt3, Vec3, addpt3, subpt3, mulpt3, divpt3, lerp3, dotvec3, crossvec3, vec3len, normvec3, identity, addm, subm, mulm, smulm, transposem, detm, tracem, adjm, invm, xform, identity3, addm3, subm3, mulm3, smulm3, transposem3, detm3, tracem3, adjm3, invm3, xform3, Quat, Quatvec, addq, subq, mulq, smulq, sdivq, dotq, invq, qlen, normq, slerp, qrotate, rframexform, rframexform3, invrframexform, invrframexform3, centroid, barycoords, centroid3, vfmt, Vfmt, GEOMfmtinstall \- computational geometry library
Flerp, fclamp, Pt2, Vec2, addpt2, subpt2, mulpt2, divpt2, lerp2, dotvec2, vec2len, normvec2, edgeptcmp, ptinpoly, Pt3, Vec3, addpt3, subpt3, mulpt3, divpt3, lerp3, dotvec3, crossvec3, vec3len, normvec3, identity, addm, subm, mulm, smulm, transposem, detm, tracem, minorm, cofactorm, adjm, invm, xform, identity3, addm3, subm3, mulm3, smulm3, transposem3, detm3, tracem3, minorm3, cofactorm3, adjm3, invm3, xform3, Quat, Quatvec, addq, subq, mulq, smulq, sdivq, dotq, invq, qlen, normq, slerp, qrotate, rframexform, rframexform3, invrframexform, invrframexform3, centroid, barycoords, centroid3, vfmt, Vfmt, GEOMfmtinstall \- computational geometry library
.SH SYNOPSIS
.de PB
.PP
@ -95,6 +95,8 @@ void smulm(Matrix m, double s);
void transposem(Matrix m);
double detm(Matrix m);
double tracem(Matrix m);
double minorm(Matrix m, int row, int col);
double cofactorm(Matrix m, int row, int col);
void adjm(Matrix m);
void invm(Matrix m);
Point2 xform(Point2 p, Matrix m);
@ -108,6 +110,8 @@ void smulm3(Matrix3 m, double s);
void transposem3(Matrix3 m);
double detm3(Matrix3 m);
double tracem3(Matrix3 m);
double minorm3(Matrix3 m, int row, int col);
double cofactorm3(Matrix3 m, int row, int col);
void adjm3(Matrix3 m);
void invm3(Matrix3 m);
Point3 xform3(Point3 p, Matrix3 m);
@ -386,6 +390,16 @@ Computes the trace of
.I m
and returns the result.
.TP
.B minorm(\fIm\fP,\fIrow\fP,\fIcol\fP)
Computes the minor of
.I m
and returns the result.
.TP
.B cofactorm(\fIm\fP,\fIrow\fP,\fIcol\fP)
Computes the cofactor of
.I m
and returns the result.
.TP
.B adjm(\fIm\fP)
Transforms the matrix
.I m
@ -454,6 +468,16 @@ Computes the trace of
.I m
and returns the result.
.TP
.B minorm3(\fIm\fP,\fIrow\fP,\fIcol\fP)
Computes the minor of
.I m
and returns the result.
.TP
.B cofactorm3(\fIm\fP,\fIrow\fP,\fIcol\fP)
Computes the cofactor of
.I m
and returns the result.
.TP
.B adjm3(\fIm\fP)
Transforms the matrix
.I m

37
sys/src/libgeometry/matrix.c
View file

@ -84,6 +84,24 @@ tracem(Matrix m)
return m[0][0] + m[1][1] + m[2][2];
}
double
minorm(Matrix m, int row, int col)
{
int i, j;
double subm[2][2];
for(i = 0; i < 3-1; i++)
for(j = 0; j < 3-1; j++)
subm[i][j] = m[i < row? i: i+1][j < col? j: j+1];
return subm[0][0]*subm[1][1] - subm[0][1]*subm[1][0];
}
double
cofactorm(Matrix m, int row, int col)
{
return minorm(m, row, col)*((row+col)&1 == 0? 1: -1);
}
void
adjm(Matrix m)
{
@ -238,6 +256,25 @@ tracem3(Matrix3 m)
return m[0][0] + m[1][1] + m[2][2] + m[3][3];
}
double
minorm3(Matrix3 m, int row, int col)
{
int i, j;
Matrix subm;
memset(subm, 0, sizeof subm);
for(i = 0; i < 4-1; i++)
for(j = 0; j < 4-1; j++)
subm[i][j] = m[i < row? i: i+1][j < col? j: j+1];
return detm(subm);
}
double
cofactorm3(Matrix3 m, int row, int col)
{
return minorm3(m, row, col)*((row+col)&1 == 0? 1: -1);
}
void
adjm3(Matrix3 m)
{