Module oc_solver_mod

1.

Purpose: implements a basic least-squares gradient solver

$$\fbox {$ \displaystyle \mathcal L\bold m\approx \bold D $}$$

		 $\bold R= \mathcal L\bold m_0- \bold D$ 
		 iterate { 
		 		  $\bold g= \mathcal L^*\bold R$ 
		 		  $\bold G= \mathcal L\bold g$ 
		 		  $\left (\bold m,\bold R\right )\longleftarrow$step$\left (\bold m,\bold R,\bold g,\bold G\right )$		 		 }

2.

Functions and subroutines

(a)

subroutine oc_solver_init(niter,maxmem,verb,mmovie,dmovie,resstop)

Purpose: initialize the basic solver

• niter: iterations number
• verb: verbose flag (optional)
• mmovie: model movie output flag (optional)
• dmovie: data movie output flag (optional)
• resstop: stop iterations at this residual power (optional)

(b)

subroutine oc_solver( L,S, x_,yy_, x0_,res_,op1 ...op9)

Purpose: simple solver

• L: out-of-core linear operator
• S: gradient step
• x0_: starting model tag
• res_: residual tag