topic Re: Alignment requirements in IPPI in Intel® Integrated Performance Primitives

Alignment requirements in IPPI

bensont — Tue, 08 May 2007 17:55:51 GMT

Hello,

I have a question about the alignment requirements in IPPI. I have looked through the manual and searched the forum, but have been unable to find an answer to my question.

I know that ippiMalloc will allocate memory such that eachimage row is 32-byte aligned and set the step size so that the amount of added padding can be determined. However, is this the format required for the ippi functions? More specifically, if I have a pre-existing 32-byte aligned floating point image with N rows and 7 columns(the first row starts on a 32-byte boundary, but not all rows do), can I pass this array to the ippi functions with a step size of 28? I realize that is not the same format that would be allocated by ippiMalloc, but as far as I can tell, the documentation never says that the ippiMalloc formatis required by the functions.

Thanks.

Thomas

Re: Alignment requirements in IPPI

bensont — Wed, 09 May 2007 17:50:51 GMT

Hello,

As a follow-up, I tried using the Remap function with a 32-byte aligned array having a number of columns not divisble byeight, but Remapreturned an ippStsStepErr error. Thus, it appears that the memory format allocated by ippiMalloc is required for at least the Remap function.

Regards,

Thoams

Re: Alignment requirements in IPPI

Vladimir_Dudnik — Mon, 14 May 2007 17:46:00 GMT

Hello Thoams,

there is no requirement for IPP functions to use memeory ony allocated through ippMalloc. Using od ippMalloc will just ensure you use aligned memory and so IPP functions willprovide better performance.

Regarding Remap, please check if you specifed coorect step not only for source and destination images but for pxMap and pyMap arrays as well.

Regards,
Vladimir