bbFMM on GPU Files

**************
* What's this?
**************

This software "occucal" is a C implementation of NVIDIA's "CUDA Occupancy Calculator". Most of codes and data in occucal are referenced from the NVIDIA's original Excel spreadsheet, that is, CUDA_occupancy_calculator.xls (Version 5.1).

**************
* Compile
**************

gcc -std=c99 -o occucal main.c -lm

**************
* Run
**************

./occucal (compute capability *) (shared memory size config in bytes **) (threads per block) (registers per thread) (shared memory per block in bytes)

 * Set '12' if your compute cabpability is 1.2, for example.
** Set '49152', '16384', or '32768'. [NOTE: This parameter has been newly added.]

**************
* Output 
**************

- STDOUT: "number of active warps per SM", "occupancy of warps per SM [%]", "utilisation of registers per SM [%]" and "utilisation of shared memory per SM [%]". 
- STDERR: The information that the original spreadsheet provides except for the graphs. The message can be suppressed by giving QUIET option. 

**************
* Example
**************

$ ./occucal 20 16384 64 32 2048  <-- Run

# CUDA occupancy calculator in C  <-- Output to STDERR
#(1) Selected your Compute Capability: 2.0
#(1b) Selected your Shared Memory Size Config (bytes): 16384
#(2) Entered your resource usage
# Threads Per Block: 64
# Registers Per Thread: 32
# Shared Memory Per Block (bytes): 2048
#(*) Physical Limits for GPU Compute Capability
# Threads per Warp: 32
# Warps per Multiprocessor: 48
# Threads per Multiprocessor: 1536
# Thread Blocks per Multiprocessor: 8
# Total # of 32-bit registers per Multiprocessor: 32768
# Register allocation unit size: 64
# Register allocation granularity: warp
# Registers per Thread: 63
# Shared Memory per Multiprocessor (bytes): 16384
# Shared Memory Allocation unit size: 128
# Warp allocation granularity: 2
# Maximum Thread Block Size: 1024
#(*) Allocatable thread blocks per multiprocessor
# due to Warps (2 48): 8
# due to Registers (2 32): 16
# due to Shared Memory (2048 16384): 8
#(*) Maximum Thread Blocks Per Multiprocessor
# Limited by Max Warps or Max Blocks per Multiprocessor (8 2): 16
# Limited by Registers per Multiprocessor (16 2): 0
# Limited by Shared Memory per Multiprocessor (8 2): 16
#(3) GPU Occupancy Data is displayed here
# Active Threads per Multiprocessor: 512
# Active Warps per Multiprocessor: 16
# Active Thread Blocks per Multiprocessor: 8
# Occupancy of each Multiprocessor: 33.0%
#(*) Utilization of registers and shared memory per multiprocessor
# Register: 50.0%
# Shared memory: 100.0%

16 33.0 50.0 100.0  <--- Output to STDOUT

**************
* Remark
**************

This software comes with no warranty.

- --
Toru Takahashi
May 8, 2015