pcg.m File Reference

Functions
endif	if (nargin< 5||isempty(m1)) exist_m1=0
	if (nargout > 5) T
	if (isnumeric(a)) r
endif	resvec (1, 1)
	while (resvec(iter-1, 1) > tol *resvec(1, 1)&&iter< maxit) if(exist_m1) if(isnumeric(m1)) y
endif	if (exist_m2) if(isnumeric(m2)) z
	resvec (iter-1, 2)
	if (alpha<=0.0) matrix_positive_definite
id	w ()
if(nargout > 5 &&iter > 2) T(iter-1	sqrt (beta) beta]./oldalpha
endif	resvec (iter, 1)
	warning ("pcg: eigenvalue estimate failed: iteration converged too fast.")
endif	if (exist_m1) if(isnumeric(m1)) y
	if (iter >=maxit-2) flag
Variables
	function [x, flag, relres, iter, resvec, eigest]
else	x = x0
else	exist_m1 = 1
else	exist_m2 = 1
endif	preconditioned_residual_out = false
endif	matrix_positive_definite = true
	p = zeros (size (b))
	oldtau = 1
else	r = b - feval (a, x, varargin{:})
	alpha = 1
	iter = 2
else	y = feval (m1, r, varargin{:})
else	z = feval (m2, y, varargin{:})
endif	tau = z' * r
	beta = tau / oldtau
else	w = feval (a, p, varargin{:})
endif	oldalpha = alpha
	l = eig (T)
	eigest = [min(l), max(l)]
else	resvec = resvec(:,1)
endif	flag = 0
	relres = resvec (iter-1,1) ./ resvec(1,1)

---

Function Documentation

if

(

iter >=maxit-

2

)

endif if

(

exist_m1

)

if

(

alpha<=0.

0

)

endif if

(

exist_m2

)

if

(

isnumeric(a)

)

if	(	nargout	,
		5
	)

endif if

(

)

[pure virtual]

endif resvec	(	iter	,
		1
	)

resvec	(	iter-	1,
		2
	)

endif resvec	(	1	,
		1
	)

if (nargout > 5 && iter > 2) T(iter-1 sqrt

(

beta

)

id w

(

)

[virtual]

warning

(

"pcg: eigenvalue estimate failed: iteration converged too fast."

)

while

(

resvec(iter-1, 1)

)

---

Variable Documentation

alpha = 1

beta = tau / oldtau

endif else eigest = [min(l), max(l)]

else exist_m1 = 1

else exist_m2 = 1

endif flag = 0

function[x, flag, relres, iter, resvec, eigest]

Initial value:

 pcg (a, b, tol, maxit, m1, m2, x0, varargin)



  if (nargin < 7 || isempty (x0))
    x = zeros (size (b))

iter = 2

l = eig (T)

endif matrix_positive_definite = true

endif oldalpha = alpha

oldtau = 1

p = zeros (size (b))

preconditioned_residual_out = false

else r = b - feval (a, x, varargin{:})

relres = resvec (iter-1,1) ./ resvec(1,1)

endif resvec = resvec(:,1)

endif tau = z' * r

else w = feval (a, p, varargin{:})

else x = x0

endif else y = feval (m1, r, varargin{:})

endif else z = feval (m2, y, varargin{:})