fix README.md

README.md

 # Fast Fourier Transform
 
+Fast Fourier transform (FFT) is speed-up technique for calculating discrete Fourier transform — DFT, which in turn is discrete version of continuous Fourier transform.
+
+Usage of the application: `fft use_case`\
+ `fft tests/tiny/lena_color1.bmp`\
+ `fft tests/small/lena_color2.bmp`\
+ `fft tests/primes/lena_color3.bmp`\
+ `fft tests/large/lena_color4.bmp`
+
 ## STEP 0: Create git repository (10%)
 
 Your code should be forked from this repository and hosted on code.it4i.cz as a private project with access for all teachers.
@@ -25,8 +33,7 @@ Create script that automatically check correctness of your application for at le
 1. Implement time measurement for all parallel regions using omp_get_wtime(). 
 2. Create script for run strong scalability measurement (PBS script).
 3. Evaluate strong scalability of measured regions up to 128 threads and different thread affinity (compact, scatter, balanced, none).
-4. Evaluate behaviour for domain specific parameters of your applications (project dependent, maybe none). (Blocking implementation for this project)
-5. Prepare charts for all measurements.
+4. Prepare charts for all measurements.
 
 ## STEP 6:  Presentation of your project (10%)
 

src/main.cpp

@@ -11,7 +11,7 @@
 int main(int argc, char** args) {
     //Check args
     if (argc < 2) {
-        printf("USAGE: fft lena_gray.bmp\n");
+        printf("USAGE: fft lena.bmp\n");
         return 0;
     }
     //Read input file