The following table summarizes all of the parameters used for controlling the behavior of Cssgrid.

Values for these parameters can be set by using the subroutines CSSETI, CSSETR, CSSETD for Fortran programs or the functions c_csseti, c_cssetr, and c_cssetd for C programs. or cssetp for NCL.

More in-depth understanding of the parameter settings can be obtained from reading Dr. Renka's articles in the ACM Transactions on Mathematical Software, Vol. 23, No 3, September 1997.

Parameter name | Parameter type | Description | Legal values | Default value |
---|---|---|---|---|

sig | float | value of the tension factor for the splines | any non-negative value (0. yields cubic splines; large values yield linear interpolation) | 1. |

tol | float | Tolerance to use in calculating gradient differences to terminate the iteration sequence when computing global gradients | any positive value. | 0.01 |

ttf | float | Tolerance to use in determining how accurately each tension factor should be calculated to approximate its optimum value | any positive value. | 0.01 |

nls | int | Number of nodes to use in the least squares fit. | greater than or equal to 4 | 10 |

nsg | int | Maximum number of iterations to use in the algorithm for computing automatic tension factors | greater than or equal to 2 | 10 |

isg | int | Flag to revert to calculating automatic tension factors rather than use a constant tension. Using a constant tension is effected by setting a value for the control parameter sig. If isg is 0, then a tension array is used, otherwise a constant tension is used. | Any integer | 0 |

igr | int | Flags whether global or local gradients are used (1 implies global, anything else implies local). | Any integer | 1 |

mvl | float | Fill value to use in returns for NCL functions. Used only if mvl has been changed from its default. | Any float | -8. |