Allocate temporary buffer in initialization time

[primenumber]

Motivation and Context

Allocate temporary buffer in each execution of operator is waste of time and hard to determine how mach memory are used.
After merged this PR, I will change code to allocate memory in Network::init(), that makes easier to optimize memory use.

Description

How has this been tested?

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature / Optimization (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[bo-code-review-bot]

This PR needs Approvals as follows.

• Ownership Approval for / from iizukak, tkng, ruimashita
• Readability Approval for C++ from tkng, tsawada

Please choose reviewers and requet reviews!

Click to see how to approve each reviews

You can approve this PR by triggered comments as follows.

• Approve all reviews requested to you (readability and ownership) and LGTM review
  Approval, LGTM

• Approve all ownership reviews
  Ownership Approval or OA

• Approve all readability reviews
  Readability Approval or RA

• Approve specified review targets

  • Example of Ownership Reviewer of /: Ownership Approval for / or OA for /
  • Example of Readability Reviewer of Python: Readability Approval for Python or RA for Python

• Approve LGTM review
  LGTM

See all trigger comments

Please replace [Target] to review target

• Ownership Approval
  • Ownership Approval for [Target]
  • OA for [Target]
  • Ownership Approval
  • OA
  • Approval
• Readability Approval
  • Readability Approval for [Target]
  • RA for [Target]
  • [Target] Readability Approval
  • [Target] RA
  • Readability Approval
  • RA
  • Approval
• LGTM
  • LGTM
  • lgtm

[tkng]

• Ownership Approval
• Readability Approval

[tkng]

/ready

[bo-mergebot]

⏳Merge job is queued...