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Update Memory usage of st wslda authored by Gabriel Wlazłowski's avatar Gabriel Wlazłowski
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Memory-usage-of-st-wslda.md
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...@@ -17,7 +17,7 @@ if you know that matrix elements, as well as the solution, will be real numbers ...@@ -17,7 +17,7 @@ if you know that matrix elements, as well as the solution, will be real numbers
3D version of the code diagonalizes matrix of size: 3D version of the code diagonalizes matrix of size:
`MATRIX_DIM = NX*NY*NZ*2`. `MATRIX_DIM = NX*NY*NZ*2`.
Memory needed store this matrix in memory is Memory needed store this matrix in memory is
`MATRIX_SIZE = MATRIX_DIM*ELEMENT_SIZE`. `MATRIX_SIZE = MATRIX_DIM*MATRIX_DIM*ELEMENT_SIZE`.
To execute diagonalization routine `st-wslda-3d` code needs at most: To execute diagonalization routine `st-wslda-3d` code needs at most:
`REQUIRED_MEMORY < 4*MATRIX_SIZE`, `REQUIRED_MEMORY < 4*MATRIX_SIZE`,
Factor 4 accounts for storage for matrix, storage for eigen-vectors, working space which depends on selected [diagonalization engine](Setting up diagonalization engine) and execution parameters. Factor 4 accounts for storage for matrix, storage for eigen-vectors, working space which depends on selected [diagonalization engine](Setting up diagonalization engine) and execution parameters.
...@@ -26,7 +26,7 @@ Factor 4 accounts for storage for matrix, storage for eigen-vectors, working spa ...@@ -26,7 +26,7 @@ Factor 4 accounts for storage for matrix, storage for eigen-vectors, working spa
In (quasi) 2D formulation of the problem diagonalization of full hamiltonian matrix factorizes into a series of `max(NZ/2,1)` diagonalizations of matrices of size (`NZ/2` arises from fact that there is the degeneracy of states with respect to sign of $`k_z`$ wave-vectors): In (quasi) 2D formulation of the problem diagonalization of full hamiltonian matrix factorizes into a series of `max(NZ/2,1)` diagonalizations of matrices of size (`NZ/2` arises from fact that there is the degeneracy of states with respect to sign of $`k_z`$ wave-vectors):
`MATRIX_DIM = NX*NY*2` `MATRIX_DIM = NX*NY*2`
and the corresponding matrix size is and the corresponding matrix size is
`MATRIX_SIZE = MATRIX_DIM*ELEMENT_SIZE`. `MATRIX_SIZE = MATRIX_DIM*MATRIX_DIM*ELEMENT_SIZE`.
Number of matrices diagonalized simultaneously is: Number of matrices diagonalized simultaneously is:
`NUMBER_OF_SIMULTANUES_DIAGONALIZATIONS = np / (p*q)` `NUMBER_OF_SIMULTANUES_DIAGONALIZATIONS = np / (p*q)`
where `np` is number of MPI processes (provided to mpi execution command) and `p` and `q` are input file parameters. where `np` is number of MPI processes (provided to mpi execution command) and `p` and `q` are input file parameters.
...@@ -40,7 +40,7 @@ To execute diagonalization routine `st-wslda-2d` code needs at most: ...@@ -40,7 +40,7 @@ To execute diagonalization routine `st-wslda-2d` code needs at most:
In (quasi) 1D formulation of the problem diagonalization of full hamiltonian matrix factorizes into a series of `max(NY*NZ/4,1)` diagonalizations of matrices of size: In (quasi) 1D formulation of the problem diagonalization of full hamiltonian matrix factorizes into a series of `max(NY*NZ/4,1)` diagonalizations of matrices of size:
`MATRIX_DIM = NX*2` `MATRIX_DIM = NX*2`
and the corresponding matrix size is and the corresponding matrix size is
`MATRIX_SIZE = MATRIX_DIM*ELEMENT_SIZE`. `MATRIX_SIZE = MATRIX_DIM*MATRIX_DIM*ELEMENT_SIZE`.
Number of matrices diagonalized simultaneously is: Number of matrices diagonalized simultaneously is:
`NUMBER_OF_SIMULTANUES_DIAGONALIZATIONS = np / (p*q)` `NUMBER_OF_SIMULTANUES_DIAGONALIZATIONS = np / (p*q)`
where `np` is number of MPI processes (provided to mpi execution command) and `p` and `q` are input file parameters. where `np` is number of MPI processes (provided to mpi execution command) and `p` and `q` are input file parameters.
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