sqrt.md

sqrt

Table of Contents:

Functions

sqrt

Examples

Examples

Quality of Results

Error Graph

Resource Usage

Function sqrt

template <unsigned int W_OUT, int IW_OUT, int N_ITERATIONS, unsigned int W_IN, int IW_IN>
ap_fixpt<unsigned int W_OUT, int IW_OUT> sqrt(ap_fixpt<unsigned int W_IN, int IW_IN> num)

Iterative implementation of sqrt.Takes in x as a fixed point number, returns sqrt(x).

Template Parameters:

• unsigned int W_OUT: width of the output
• int IW_OUT: width of integer portion of the output
• int N_ITERATIONS: number of iterations
• unsigned int W_IN: width of the input (automatically inferred)
• int IW_IN: width of integer portion of the input (automatically inferred)

Function Arguments:

• ap_fixpt<unsigned int W_IN, int IW_IN> num: input

Returns:

• ap_fixpt<unsigned int W_OUT, int IW_OUT>: square root of input value

Examples

  hls::ap_fixpt<10, 2> y = 4;

  auto x = hls::math::sqrt<10, 2, 20>(y); //x will be an ap_fixpt w/ the value 2

The example used to gather the following graph and resource report can be found here.

Error Graph

Resource Usage

Using MPF300

Input Plot Range: [0.00, 1.00] Using N_ITER = 16 Using W = 32, IW = 8, Q_M = AP_TRN, O_M = AP_WRAP

Name	Latency [cycles] (min/max/avg)	II [cycles] (min/max/avg)	Avg Error	Max Error	LUTs	DFFs	DSPs	LSRAM	uSRAM	Estimated Frequency
sqrt_cmath	6 / 262 / 218.28	6 / 262 / 218.48	0	0	12584	16173	6	0	0	280.584 MHz
sqrt_hls	84 / 85 / 84.01	1 / 2 / 1.01	7e-06	1.5e-05	2690	4649	0	0	7	419.992 MHz

Input Plot Range: [1.00, 100.00] Using N_ITER = 16 Using W = 32, IW = 16, Q_M = AP_TRN, O_M = AP_WRAP

Name	Latency [cycles] (min/max/avg)	II [cycles] (min/max/avg)	Avg Error	Max Error	LUTs	DFFs	DSPs	LSRAM	uSRAM	Estimated Frequency
sqrt_cmath	6 / 262 / 218.28	6 / 262 / 218.48	0	0	12584	16173	6	0	0	280.584 MHz
sqrt_hls	102 / 103 / 102.01	1 / 2 / 1.01	9.9e-05	0.000244	3542	6298	0	0	6	430.663 MHz

Input Plot Range: [0.00, 4294967295.00] Using N_ITER = 30 Using W = 33, IW = 32, Q_M = AP_TRN, O_M = AP_WRAP

Name	Latency [cycles] (min/max/avg)	II [cycles] (min/max/avg)	Avg Error	Max Error	LUTs	DFFs	DSPs	LSRAM	uSRAM	Estimated Frequency
sqrt_cmath	6 / 262 / 218.28	6 / 262 / 218.48	0	0	12584	16173	6	0	0	280.584 MHz
sqrt_hls	185 / 186 / 185.20	1 / 2 / 1.25	0.052281	0.159138	8763	22283	0	1	26	338.409 MHz

Input Plot Range: [0.00, 10.00] Using N_ITER = 16 Using W = 32, IW = 16, Q_M = AP_TRN, O_M = AP_WRAP

Name	Latency [cycles] (min/max/avg)	II [cycles] (min/max/avg)	Avg Error	Max Error	LUTs	DFFs	DSPs	LSRAM	uSRAM	Estimated Frequency
sqrt_cmath	6 / 262 / 218.28	6 / 262 / 218.48	0	0	12584	16173	6	0	0	280.584 MHz
sqrt_hls	102 / 103 / 102.01	1 / 2 / 1.01	2.9e-05	0.00012	3542	6298	0	0	6	430.663 MHz

Notes:

• The standard C math library uses floating point numbers.
• Targeted FMax was 400MHz.

Back to top.