Resolving RuntimeWarning: divide by zero encountered in double_scalars

Table of Contents Solve “RuntimeWarning: divide by zero encountered in double_scalars” Problem Description Cause Analysis Solution 1. Check if the divisor is zero 2. Use try-except statement to capture warning information 3. Disable warning messages Summarize Practical application scenarios Sample code Solution”RuntimeWarning: divide by zero encountered in double_scalars” Problem Description When using Python for scientific […]

Scalar diffraction calculation guide (python implementation)

Scalar Diffraction Calculation Guide (Python Implementation) Introduction The purpose of this article is to summarize some calculation methods of scalar diffraction and discuss their applicable conditions. Code and examples are at: https://github.com/zhemglee/Scalardiffraction Required prerequisite knowledge: The mathematical knowledge involved is not advanced, mainly the basic knowledge of linear systems and Fourier transform (discrete Fourier transform), […]

ORCA optimizer analysis – CDXLScalarFilter Class for DXL filter operators

CDXLScalarFilter CDXLScalarFilter is Class for representing DXL filter operators. CDXLScalarFilter does not add other data members relative to CDXLScalar. class CDXLScalarFilter : public CDXLScalar{<!– –> private: CDXLScalarFilter(CDXLScalarFilter & amp;); // private copy ctor public: explicit CDXLScalarFilter(CMemoryPool *mp); // ctor/dtor Edxlopid GetDXLOperator() const; // accessors const CWStringConst *GetOpNameStr() const; // serialize operator in DXL format virtual […]

Analysis of ORCA optimizer – QueryToDXL (CDXLLogical+CDXLScalar) main process

Orca is a new query optimizer for Pivotal’s data management products, including GPDB and HAWQ. Orca is a modern top-down query optimizer based on the Cascades operational timing framework. While many Cascades optimizers are tightly coupled to their host system, a unique feature of Orca is its ability to operate outside of the database system […]

Minimum Scalar Product

Description of topic: Problem You are given two vectors v 1 v1 v1 = (x1, x2, …, xn) and v 2 v2 v2 = (y1, y2, …, yn). The scalar product of these vectors is a single number, calculated as x1y1 + x2y2 + … + xnyn. Suppose you are allowed to permute the coordinates […]

Read the Aggregate (aggregate) function and Scalar (standard) function in SQL in one article

Directory Foreword: 1. SQL Aggregate function 1. AVG() function 2. count() function 3. MAX() function 4. MIN() function 5. SUM() function 6. SQL GROUP BY syntax 7. SQL HAVING clause 8. SQL EXISTS operator 9. SQL UNION operator 2. SQL Scalar function 1. SQL UCASE() function 2. SQL LCASE() function 3. SQL MID() function 4. […]

Table-valued and scalar functions in sqlserver

Directory 1. Table-valued functions 1. Inline table-valued functions 1. Create a function 2. Call the function 3. Return the result 2. Multi-statement table-valued function 2. Call the function 3. Return the result 3. The difference between inline table-valued functions and multi-statement table-valued functions 1. Grammatically 2. Structurally 2. Scalar function 1. Create a function 2. […]