Hypergeometric tail calculations

Overview

The phyper library (pronounced "viper") computes the cumulative probability for a hypergeometric distribution, intended for testing overrepresentation of pathways/signatures within the set of marker genes. The interface is based on R's stats::phyper() function, with support for (log-transformed) probabilities of either tail.

Quick start

#include "phyper/phyper.hpp"
 
phyper::Options opt;
opt.upper_tail = true;
opt.log = false;
 
// Equivalent to stats::phyper(5-1, 20, 10000, 100, lower.tail=FALSE)
phyper::compute(
    /* number of marker genes from the pathway */ 5, 
    /* number of genes in the pathway */ 20, 
    /* number of genes not in the pathway */ 10000,
    /* number of marker genes */ 100,
    opt
);

Note that the upper-tailed cumulative probability returned by phyper::compute() includes the probability mass of the observed number of marker genes in the pathway. This means that it can be directly used as the overrepresentation p-value for the pathway. For comparable results from stats::phyper(), users should subtract 1 from the q= argument as inicated above.

Check out the reference documentation for more details.

Building projects

CMake with FetchContent

If you're using CMake, you just need to add something like this to your CMakeLists.txt:

include(FetchContent)
 
FetchContent_Declare(
  phyper
  GIT_REPOSITORY https://github.com/libscran/phyper
  GIT_TAG master # or any version of interest
)
 
FetchContent_MakeAvailable(phyper)

Then you can link to phyper to make the headers available during compilation:

# For executables:
target_link_libraries(myexe libscran::phyper)
 
# For libaries
target_link_libraries(mylib INTERFACE libscran::phyper)

CMake with find_package()

find_package(libscran_phyper CONFIG REQUIRED)
target_link_libraries(mylib INTERFACE libscran::phyper)

To install the library, use:

mkdir build && cd build
cmake .. -DNENESUB_TESTS=OFF
cmake --build . --target install

Manual

If you're not using CMake, the simple approach is to just copy the files in include/ - either directly or with Git submodules - and include their path during compilation with, e.g., GCC's -I.T