r83
    
    
    
      r83,
      an Octave code which 
      carries out some basic linear algebra operations on R83 matrices
      (real 64 bit precision tridiagonal 3xN format).
    
    
      Licensing:
    
    
      The information on this web page is distributed under the MIT license.
    
    
      Languages:
    
    
      r83 is available in 
      a C version  and 
      a C++ version  and 
      a Fortran90 version  and 
      a MATLAB version and 
      an Octave version and 
      a Python version.
    
    
      Related Data and Programs:
    
 
    
      
      r83_test
    
  
    
      
      linear_algebra,
      an Octave code which 
      carries out various linear algebra operations for matrices
      stored in a variety of formats.
    
    
      Source Code:
    
    
      
        - 
          i4_log_10.m, 
          returns the integer part of the logarithm base 10 of abs(X);
        
 
        - 
          r8_uniform_01.m, 
          returns a pseudorandom R8.
        
 
        - 
          r83_cg.m, 
          solves an R83 system using the conjugate gradient method.
        
 
        - 
          r83_cr_fa.m, 
          factors an R83 system using cyclic reduction;
        
 
        - 
          r83_cr_sl.m, 
          solves an R83 system factored by r83_cr_fa;
        
 
        - 
          r83_cr_sls.m, 
          solves several R83 systems factored by r83_cr_fa;
        
 
        - 
          r83_dif2.m, 
          returns the second difference matrix as an R83.
        
 
        - 
          r83_jac_sl.m, 
          solves an R83 system using Gauss-Seidel iteration;
        
 
        - 
          r83_indicator.m, 
          sets up an R83 indicator matrix;
        
 
        - 
          r83_jac_sl.m, 
          solves an R83 system using Jacobi iteration;
        
 
        - 
          r83_mtv.m, 
          multiplies a vector times an R83 matrix;
        
 
        - 
          r83_mv.m, 
          multiplies an R83 matrix times a vector;
        
 
        - 
          r83_print.m, 
          prints an R83 matrix;
        
 
        - 
          r83_print_some.m, 
          prints some of an R83 matrix;
        
 
        - 
          r83_random.m, 
          randomizes an R83 matrix;
        
 
        - 
          r83_res.m, 
          returns the residual of an R83 linear system.
        
 
        - 
          r83_to_r8ge.m, 
          copies an R83 matrix to an R8GE matrix;
        
 
        - 
          r83_zeros.m, 
          zeros an R83 matrix;
        
 
        - 
          r8ge_indicator.m, 
          returns the indicator R8GE matrix.
        
 
        - 
          r8ge_mtv.m, 
          multiplies an R8GE matrix transposed times a vector.
        
 
        - 
          r8ge_mv.m, 
          multiplies an R8GE matrix times a vector.
        
 
        - 
          r8ge_print.m, 
          prints an R8GE matrix;
        
 
        - 
          r8ge_print_some.m, 
          prints some of an R8GE matrix;
        
 
        - 
          r8vec_indicator1.m, 
          sets an R8VEC to the indicator1 vector;
        
 
        - 
          r8vec_print.m, 
          prints an R8VEC;
        
 
        - 
          r8vec_uniform_01.m, 
          returns a random R8VEC;
        
 
        - 
          r8vec2_print.m, 
          prints a pair R8VEC's;
        
 
      
    
    
    
      Last revised on 16 May 2023.