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Contents
Usage:
y <- csubscr(x,I), REAL matrix x containing complex matrix X in fully
complex form, legal REAL or LOGICAL subscript or NULL I
y <- csubscr(x,I,J), legal REAL or LOGICAL subscripts or NULL, I and J
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Keywords:
complex matrices, matrices
Usage
csubscr() simulates subscript extraction from a complex vector X or m by
n complex matrix X stored in REAL matrix x in fully complex form (real
parts in odd columns, imaginary parts in even columns). The result y
contains a complex vector or matrix Y in fully complex form.
y <- csubscr(x,I) simulates Y <- X[I,] when I is a vector or Y <- X[I]
when I is a matrix with two columns. When I is empty or NULL, it
simulates Y <- X[].
y <- csubscr(x,I,J) simulates Y <- X[I,J]. When I is empty or NULL it
simulates Y <- X[,J]; when J is empty or NULL it simulates Y <- X[I,].
y <- csubscr(x) is equivalent to cmplx(creal(x),cimag(y)).
Caution
Unlike real subscripts you cannot assign to csubscr(x, I, J).
Example
Example with 2 by 4 REAL a representing 2 by 2 complex A:
Cmd> creal(a) # real part
(1,1) 0.57 -0.33
(2,1) -0.24 -0.55
Cmd> cimag(a) # imaginary part
(1,1) 0.43 -0.16
(2,1) -0.08 0.26
Cmd> csubscr(a,1,2) # simulates A[1,2]
(1,1) -0.33 -0.16
Cmd> csubscr(a,hconcat(run(2),run(2))) # simulates cdiag(a)
(1,1) 0.57 0.43
(2,1) -0.55 0.26
Cmd> csubscr(a,,-1) # or csubscr(a,NULL,-1), simulates A[,-1]
(1,1) -0.33 -0.16
(2,1) -0.55 0.26
Cross references
See also cdiag(), 'complex', 'subscripts', creal(), cimag().
Gary Oehlert
2006-01-30