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Change width to size, as it is more correct.

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Add calculation of determinant, submatric, minorm cofactor and inverse of a matrix.
This commit is contained in:
Godzil
2020-02-14 19:19:36 +00:00
parent 9f2a41e6f3
commit 0621ca86e1
3 changed files with 325 additions and 33 deletions
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104
source/matrix.cpp
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@@ -7,6 +7,7 @@
*
*/
#include <stdio.h>
#include <matrix.h>
#include <tuples.h>
#include <math_helper.h>
@@ -15,7 +16,7 @@ Matrix::Matrix(int width)
{
int i;
this->width = width;
this->size = width;
for(i = 0; i < width*width; i++)
{
@@ -27,13 +28,13 @@ Matrix::Matrix(double values[], int width)
{
int x, y;
this->width = width;
this->size = width;
for(y = 0; y < this->width; y++)
for(y = 0; y < this->size; y++)
{
for (x = 0 ; x < this->width ; x++)
for (x = 0 ; x < this->size ; x++)
{
this->data[this->width * x + y] = values[this->width * x + y];
this->data[this->size * x + y] = values[this->size * x + y];
}
}
};
@@ -41,13 +42,13 @@ Matrix::Matrix(double values[], int width)
bool Matrix::operator==(const Matrix &b) const
{
int i;
if (this->width != b.width)
if (this->size != b.size)
{
/* If they are not the same size don't even bother */
return false;
}
for(i = 0; i < this->width*this->width; i++)
for(i = 0; i < this->size*this->size; i++)
{
if (!double_equal(this->data[i], b.data[i]))
{
@@ -61,13 +62,13 @@ bool Matrix::operator==(const Matrix &b) const
bool Matrix::operator!=(const Matrix &b) const
{
int i;
if (this->width != b.width)
if (this->size != b.size)
{
/* If they are not the same size don't even bother */
return true;
}
for(i = 0; i < this->width*this->width; i++)
for(i = 0; i < this->size*this->size; i++)
{
if (!double_equal(this->data[i], b.data[i]))
{
@@ -80,16 +81,16 @@ bool Matrix::operator!=(const Matrix &b) const
Matrix Matrix::operator*(const Matrix &b) const
{
int x, y, k;
Matrix ret = Matrix(this->width);
Matrix ret = Matrix(this->size);
if (this->width == b.width)
if (this->size == b.size)
{
for (y = 0 ; y < this->width ; y++)
for (y = 0 ; y < this->size ; y++)
{
for (x = 0 ; x < this->width ; x++)
for (x = 0 ; x < this->size ; x++)
{
double v = 0;
for (k = 0 ; k < this->width ; k++)
for (k = 0 ; k < this->size ; k++)
{
v += this->get(x, k) * b.get(k, y);
}
@@ -111,7 +112,7 @@ Tuple Matrix::operator*(const Tuple &b) const
Matrix Matrix::identity()
{
int i;
for(i = 0; i < this->width; i++)
for(i = 0; i < this->size; i++)
{
this->set(i, i, 1);
}
@@ -121,13 +122,80 @@ Matrix Matrix::identity()
Matrix Matrix::transpose()
{
int x, y;
Matrix ret = Matrix(this->width);
for (y = 0 ; y < this->width ; y++)
Matrix ret = Matrix(this->size);
for (y = 0 ; y < this->size ; y++)
{
for (x = 0 ; x < this->width ; x++)
for (x = 0 ; x < this->size ; x++)
{
ret.set(y, x, this->get(x, y));
}
}
return ret;
}
Matrix Matrix::submatrix(int row, int column)
{
int i, j;
int x = 0, y = 0;
Matrix ret = Matrix(this->size - 1);
for (i = 0 ; i < this->size ; i++)
{
if (i == row)
{
/* Skip that row */
continue;
}
y = 0;
for (j = 0 ; j < this->size ; j++)
{
if (j == column)
{
/* skip that column */
continue;
}
ret.set(x, y, this->get(i, j));
y++;
}
x++;
}
return ret;
}
double Matrix::determinant()
{
double det = 0;
if (this->size == 2)
{
det = this->data[0] * this->data[3] - this->data[1] * this->data[2];
}
else
{
int col;
for(col = 0; col < this->size; col++)
{
det = det + this->get(0, col) * this->cofactor(0, col);
}
}
return det;
}
Matrix Matrix::inverse()
{
Matrix ret = Matrix(this->size);
if (this->isInvertible())
{
int row, col;
double c;
for (row = 0; row < this->size; row++)
{
for (col = 0; col < this->size; col++)
{
c = this->cofactor(row, col);
ret.set(col, row, c / this->determinant());
}
}
}
return ret;
}