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CORDIC-based absolute value
r = cordicabs(c)
r = cordicabs(c,niters)
r = cordicabs(c,niters,'ScaleOutput',b)
r = cordicabs(c,'ScaleOutput',b)
r = cordicabs(c) returns the magnitude of the complex elements of C.
r = cordicabs(c,niters) performs niters iterations of the algorithm.
r = cordicabs(c,niters,'ScaleOutput',b) specifies both the number of iterations and, depending on the Boolean value of b, whether to scale the output by the inverse CORDIC gain value.
r = cordicabs(c,'ScaleOutput',b) scales the output depending on the Boolean value of b.
c |
c is a vector of complex values. |
niters |
niters is the number of iterations the CORDIC algorithm performs. This argument is optional. When specified, niters must be a positive, integer-valued scalar. If you do not specify niters, or if you specify a value that is too large, the algorithm uses a maximum value. For fixed-point operation, the maximum number of iterations is the word length of r or one less than the word length of theta, whichever is smaller. For floating-point operation, the maximum value is 52 for double or 23 for single. Increasing the number of iterations can produce more accurate results but also increases the expense of the computation and adds latency. |
Optional comma-separated pairs of Name,Value arguments, where Name is the argument name and Value is the corresponding value. Name must appear inside single quotes ('').
Compare cordicabs and abs of double values.
dblValues = complex(rand(5,4),rand(5,4)); r_dbl_ref = abs(dblValues) r_dbl_cdc = cordicabs(dblValues)
Compute absolute values of fixed-point inputs.
fxpValues = fi(dblValues); r_fxp_cdc = cordicabs(fxpValues)
[1] Volder, JE. "The CORDIC Trigonometric Computing Technique." IRE Transactions on Electronic Computers. Vol. EC-8, September 1959, pp. 330–334.
[2] Andraka, R. "A survey of CORDIC algorithm for FPGA based computers." Proceedings of the 1998 ACM/SIGDA sixth international symposium on Field programmable gate arrays. Feb. 22–24, 1998, pp. 191–200.
[3] Walther, J.S. "A Unified Algorithm for Elementary Functions." Hewlett-Packard Company, Palo Alto. Spring Joint Computer Conference, 1971, pp. 379–386. (from the collection of the Computer History Museum). www.computer.org/csdl/proceedings/afips/1971/5077/00/50770379.pdf
[4] Schelin, Charles W. "Calculator Function Approximation." The American Mathematical Monthly. Vol. 90, No. 5, May 1983, pp. 317–325.