ipprWarpAffine bug

[Ken_Thornton]

I'm running tests on ipprWarpAffine and get failures for certain permutation matrices. 

My IPP build is 58644 (April 6, 2018). I'm running on Windows 7 (Intel Core i7) and using the ia32_win IPP libraries.

Below is a simple example to illustrate the problem.

void TestWarpAffine()
{
	double coefs[3][4] ={{0.0, 0.0, 1.0, 0.0}, {1.0, 0.0, 0.0, 0.0}, {0.0, 1.0, 0.0, 0.0}};
	unsigned char in[27] ={0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26};
	unsigned char out[27] ={0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

	IpprVolume srcSize ={3,3,3}, dstSize ={3,3,3};
	IpprCuboid srcVOI ={0,0,0,3,3,3}, dstVOI ={0,0,0,3,3,3};

	//Step 1: Allocate buffer
	int nBufferSize = 0;
	IppStatus sts = ipprWarpAffineGetBufSize(srcSize, srcVOI, dstVOI, coefs, 1, ippLinear, &nBufferSize); //1 means 1 channel
	ASSERT(sts == ippStsOk && nBufferSize >= 0);
	nBufferSize = __max(nBufferSize, 10); //Protect against allocating 0 bytes
	Ipp8u* pBuffer = ippsMalloc_8u(nBufferSize);
	ASSERT(pBuffer != NULL);

	//Step 2: Warp
	sts = ipprWarpAffine_8u_C1V(in, srcSize, 3, 9, srcVOI, out, 3, 9, dstVOI, coefs, ippLinear, pBuffer); //3 bytes between rows, 9 bytes between planes
	ippsFree(pBuffer);
	ASSERT(sts == ippStsOk); //Will get sts == -56

	const IppLibraryVersion* pVer = ippGetLibVersion();
}

[Gennady_F_Intel]

is that 64 or 32 bit code or both?

[Gennady_F_Intel]

-56 error code means that ippStsCoeffErr          determinant of the transform matrix Aij is equal to zero. if you will fix this - your case will work.

[Ken_Thornton]

Gennady,

No the determinant is 1, not 0. So it is invertible.

https://software.intel.com/en-us/ipp-dev-reference-warpaffine

If p is a 3D point in the source volume and q is a 3D point in the destination volume:

      | 0 0 1 |       | 0 |

q = | 1 0 0 | p + | 0 |

      | 0 1 0 |       | 0 |

The inverse transformation is:

       | 0 1 0 |

p =  | 0 0 1 | q

       | 1 0 0 |

                                       -1

            | 0 1 0 |      | 0 0 1 |

Since   | 0 0 1 |  =  | 1 0 0 |

            | 1 0 0 |      | 0 1 0 |

[Gennady_F_Intel]

Ken, we confirmed the problem and will add the fix into one of the nearest updates. We will keep you updated with the status of this issue. Thanks for report. 

[Gennady_F_Intel]

the fix of the problem available since IPP 2019 u1 and the latest 2020 versions as well.