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Re: Accelerate/vDSP.h question
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Re: Accelerate/vDSP.h question


  • Subject: Re: Accelerate/vDSP.h question
  • From: Roland King <email@hidden>
  • Date: Tue, 28 Feb 2012 21:19:59 +0800

I put that code in a main() function in a new 10.7 project with Xcode 4.2.1 (no idea why I'm still on that version) and at the breakpoint, bb has the abs of aa. Tried debug and release builds, works fine.



On Feb 28, 2012, at 8:43 PM, Jan E. Schotsman wrote:

>
> On Feb 28, 2012, at 6:36 AM, Don Thompson wrote:
>
>> Have the vDSP functions vDSP_vabs and vDSP_vabsD recently changed?  They seem to be no longer working  other than to simply return an unchanged version of an input.
>>
>> Here is a simple, Cocoa test routine I used to prove the point:
>> 	unsigned int	ii;
>> 	double		aa[10], bb[10];
>> 	for( ii=0; ii<10; ii++ ) { aa[ii]=1.1, bb[ii]=0; }
>> 	aa[1]=aa[3]=aa[6]=-2.2;
>> 	vDSP_vabsD( aa, 1, bb, 1, 10 );
>> 	ii = 0;
>> with breakpoints set at the "aa[1] ..." and "ii=0" lines.
>>
>> The aa array is as expected at the 1st breakpoint; unfortunately, at the 2nd breakpoint, the bb array matches aa rather than an absolute value version of aa.
>
> This is a question for the performance-dev list.
> Does the problem go away if you malloc the arrays?
>
> Jan E.
>
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References: 
 >Re: Accelerate/vDSP.h question (From: "Jan E. Schotsman" <email@hidden>)

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