Matrix inverse
Am I correct in saying that a matrix multiplied by its inverse = an identity matrix?
Then why don''t I get an identity matrix back when I use D3DXMatrixInverse and D3DXMatrixDeterminant to calculate the inverse then multiply the two together? My origional matrix equals camera view * a projection matrix which is then transposed.
The inverse of 2 is 0.5 meaning 2 * 0.5 = 1 which you could say is the identity matrix of a 1x1 matrix.
Well to be fair, numbers have additive inverses as well as multiplicative inverses.
2 and -2 are additive inverses.
2 and 0.5 are multiplicative inverses.
Generally, when referring to matrices, you''re referring to the multiplicative inverse (the additive inverse isn''t as useful, especially with 3D work).
Josh
2 and -2 are additive inverses.
2 and 0.5 are multiplicative inverses.
Generally, when referring to matrices, you''re referring to the multiplicative inverse (the additive inverse isn''t as useful, especially with 3D work).
Josh
There are a couple of things to remember here. First, any square matrix which has a determinant of 0 has an undefined inverse. Second, double-check the order in which you multiply the inverse and the original.
It should be: A*inv(A) = I
It should be: A*inv(A) = I
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