Dierckx: B-Splines Curve and Surface Fitting

Dierckx is a Fortran library for fitting curve and surface B-Splines to sets of data points. It was written by Paul Dierckx in the mid 1980s, and it is still the most advanced general B-spline fitting library today. It is based on a solid mathematical foundation, implements many advanced algorithms, and is described in detail in Paul Dierckx' book: Curve and Surface Fitting with Splines.

Usage

You need a Fortran compiler on your system to use this library: in specific, at the moment, it requires the Gnu Fortran GFortran compiler to be installed. See Installing GFortran how to do this on your machine.

Having to install a Fortran compiler is a big restriction, so I recommend not using this crate as a dependency in big projects.

The Fortran files are located in the src/netlib-dierckx directory, and were downloaded from the netlib.org server on Oct 12, 2021. The code was adapted to fix some warnings, in specific the float equality comparisons, which were replaced with the abs(f)<epsilon(f) pattern when checking for a 0.0 value, and the abs(fa-fb)<epsilon(fa)-pattern, to check between equality of two REAL numbers. The files use REAL precision floating point values, but are cast to Rust f64 values using the -fdefault-real-8 gfortran compiler flag. The original Fortran files do not define any double precision values.

The Fortran compilation is performed using the build.rs script, which uses the cc crate, and the gfortran compiler, and sets the following compiler flags:

• -std=legacy
• -fdefault-real-8 cast all single precision floats to f64
• -Wno-maybe-uninitialized
• -O3 highest optimization for gfortran

To use this library add this to your Cargo.toml file:

[dependencies]
dierckx-sys = "0.1.0"

For further instructions and examples see the separate dierckx crate.

License

The Dierckx' Fortran code, included in this repository, was downloaded from netlib.org, and has no license restrictions, but please acknowledge Paul Dierckx' work and library in your projects.

All the other content in this repository is ©2021 Harbers Bik LLC, and licensed under either of

• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT?)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.