Parameter: nzero

Definition

Maximum allowed number of non-zero elements in $F$-matrix. In the iQIST software package, the terminology $F$-matrix denotes the $d$ operator (the destroy operator for impurity electron) matrix in the eigen-basis of the local Hamiltonian or in occupation number basis.

Type

Integer

Default value

128

Component

Only for the BEGONIA, LAVENDER, and CAMELLIA components.

Behavior

In the BEGONIA, LAVENDER, and CAMELLIA components, we used the sparse matrix technology to accelerate the matrix times vector operation (spmv) and matrix times matrix (spmm). In order to save the memory, the $F$-matrix, the local Hamiltonian matrix, and the product matrix of the above operations are stored in CSR format. Here, we used nzero parameter to describe the maximum allowed number of non-zero elements of these matrices, and allocate the corresponding memories.

In the spmm operations, sometimes the number of the non-zero elements in the resulted matrix exceeds the value of nzero, which will trigger a fatal error/exception. At that time, you have to increase nzero by twofold, and redo the calculation.

Comment

In the BEGONIA and LAVENDER components the $F$-matrix mean the $d$ operator matrix in the eigen-basis. However, in the CAMELLIA component, it means the $d$ operator matrix in the occupation number basis.