Fimath function

I need to compute T=C*X where C and X are 8*8 matrices (Matrix multiplication includes multiplication of corresponding rows and colums followed by addition)

the wordlength for my multiplier module is 16 bits and adder module is 17 bits....

1)How can this be done using fimath function..... 2)How can i verify the results that I'm getting is correct ,if i'm using the above mentioned wordlengths......

can anyone explain?

Answer 1

[Hong Ye]

Hi, you can achieve this by using fi object

Cm = fi(rand(8,8), 1, 16);
Xm = fi(rand(8,8), 1, 16);
F1 = fimath('ProductMode','keepMSB',...
  'ProductWordLength',16, ...
      'SumMode', 'SpecifyPrecision',...
      'SumWordLength',17,...
      'SumFractionLength',14);
Cm.fimath = F1;
Tm = Cm*Xm;

you can compare you fixed-point result with floating-point reference result to check for numerical correctness and quantization error. you can adjust following "knobs" to minimize quantization errors,

• ProducMode
• SumFractionLength if SumMode is 'SpecifyPrecision'
• SumMode
• ProductFractionLength if ProductMode is 'SpecifyPrecision'

hope it helps.