ePOM - Intro to Ocean Data Science - Scientific Computing

ePOM - Intro to Ocean Data Science - Scientific Computing

• 1.
  SCIENTIFIC COMPUTING GIUSEPPE MASETTI ESCI872 – APPLIED TOOLS FOR OCEAN MAPPING – INTRODUCTION TO OCEAN DATA SCIENCE Durham, NH – September 5, 2019 V0
• 2.
  WHAT IS SCIENTIFICCOMPUTING? • Implementation of methods to solve problems with computers • The problems come from many fields → Interdisciplinary (source: wikiversity.org) UNDERWATER ACOUSTICS SCIENTIFIC COMPUTING Acoustic Ray Tracing Z Solution Method
• 3.
  SCIENTIFIC COMPUTING WITHPYTHON • Efficient storage/manipulation of N-dimensional numerical arrays • NumPy also provides: • Linear algebra • Fourier transform • Functions to create random numbers • ...
• 4.
  PYTHON SCIENTIFIC STACK
• 5.
  PYTHON LISTS VSNUMPY ARRAYS • A Python int is not just an integer: (VanderPlas, Python Data Science Handbook, 2017) language: C struct _longobject { long ob_refcnt; PyTypeObject *ob_type; size_t ob_size; long ob_digit[1]; }; Reference count: used to handle memory allocation Object type: used to store the type of the variable Object size: used to specify the size of next member Actual integer value!!! language: Python x = 8
• 6.
  PYTHON LISTS VSNUMPY ARRAYS • A Python int is not just an integer: language: Python x = 8 PyObject Info Value: 8
• 7.
  PYTHON LISTS VSNUMPY ARRAYS • A Python int is not just an integer: language: Python x = 8 PyObject Info Value: 8 • A Python list is more than just a list of values: language: Python a = [8, 3.14, "hi"] PyObject Info Length Items PyObject Info Value: 3.14 0x88808 0x88810 0x88818 PyObject Info Value: "hi" PyObject Info Value: 8
• 8.
  PYTHON LISTS VSNUMPY ARRAYS • A NumPy array has a fixed type: language: Python import numpy as np b = np.array([8, 4, 1]) 8 4 1 PyObject Info Data Data Type Dimensions Strides Data Type Description int8 Integer (-128 to 127) int16 Integer (-32768 to 32767) int32 Integer (-2147483648 to 2147483647) int64 Integer (-9223372036854775808 to 9223372036854775807) uint8 Unsigned integer (0 to 255) uint16 Unsigned integer (0 to 65535) uint32 Unsigned integer (0 to 4294967295) uint64 Unsigned integer (0 to 18446744073709551615) Data Type Description intp Integer used for indexing bool Boolean (True or False) float16 Half precision float float32 Single precision float float64 Double precision float complex64 Complex number, represented by two float32 complex128 Complex number, represented by two float64 ... …
• 9.
  PYTHON LISTS VSNUMPY ARRAYS • A NumPy array may have more than 1 dimension: language: Python import numpy as np a = np.random.rand(3) b = np.random.rand(3, 5) c = np.random.rand(3, 5, 4) d = ... a 0 1 2 b c
• 10.
  • NumPy hasa huge number of functionalities! • Consult the Numpy Reference Manual. • Find your favorite publicly-available cheat sheet → For instance:
• 11.
  MODULE TASK →ADOPT NUMPY ARRAYS
• 12.
  GO TO “INTRODUCTIONTO NUMPY” NOTEBOOK
• 13.
  QUESTIONS? Contact me at:gmasetti@ccom.unh.edu